This invention relates to an apparatus which is installed in an automatic money exchange machine and which detects the thickness of a bank note.
Heretofore, the determination of the genuineness of a bank note deposited in an automatic money exchange machine, or the like, has been mainly carried out by reading the pattern of a portion of the bank note and collating the read-out pattern with reference data. If a system of reading only the pattern of one portion of a bank note is adopted, however it cannot be categorically said that there is no possibility of a fabricated bank note, such as one made by cutting a bank note into slender strips and connecting some of them by using adhesive tape (see FIG. 9), being erroneously recognized and accepted as a genuine one.
To detect such a fabricated bank note, devices such as an "Apparatus for Detecting the Thickness of Paper and the Like" disclosed in the publication of Japanese Patent Public Disclosure No. 60592/1984 have been proposed.
This detection apparatus adopts a system in which, as shown in FIGS. 7 and 8, a planar detection arm 4 which is vertically rotatable about a shaft 3 as center is made to come into contact with a bank note 2 being transported on rolls 1, and the angle of rotation of the shaft 3 caused by the vertical movement of the detection arm 4 in accordance with the thickness of the bank note 2 is detected by a potentiometer 5. This detection apparatus is designed so that it can detect the change in an output signal from the potentiometer 5 when the detection arm 4 rotates (in the clockwise direction as viewed in FIG. 7) when a piece of adhesive tape (with a thickness of approximately 0.03 mm) which is thinner than the bank note 2 (with a thickness of about 0.09 mm) passes below the detection arm 4, thereby enabling the rejection of a fabricated bank note.
However, the detection apparatus of the above-described method is capable of detecting a fabricated bank note only when a piece of adhesive tape 6 passes below the detection arm 4, as shown in FIG. 9. Therefore, it is possible that such a detection apparatus will be incapable of detecting a fabricated bank note when a bank note strip 7 of a narrow width passes below the detection arm 4.
Accordingly, it is conceivable to provide a plurality of detection apparatuses, each constituted by a detection arm 4 and a potentiometer 5. However, this arrangement has the problem that it increases the cost of the apparatus.